Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada
Bibliographic record
Abstract
Abstract Tundra‐atmosphere exchanges of carbon dioxide (CO 2 ) and water vapour were measured near Daring Lake, Northwest Territories in the Canadian Low Arctic for 3 years, 2004–2006. The measurement period spanned late‐winter until the end of the growing period. Mean temperatures during the measurement period varied from about 2 °C less than historical average in 2004 and 2005 to 2 °C greater in 2006. Much of the added warmth in 2006 occurred at the beginning of the study, when snow melt occurred 3 weeks earlier than in the other years. Total precipitation in 2006 (163 mm) was more than double that of the driest year, 2004 (71 mm). The tundra was a net sink for CO 2 carbon in all years. Mid‐summer net ecosystem exchange of CO 2 (NEE) achieved maximum values of −1.3 g C m −2 day −1 (2004) to −1.8 g C m −2 day −1 (2006). Accumulated NEE values over the 109‐day period were −32,−51 and −61 g C m −2 in 2004, 2005 and 2006, respectively. The larger CO 2 uptake in 2006 was attributed to the early spring coupled with warmer air and soil conditions. In 2004, CO 2 uptake was limited by the shorter growing season and mid‐summer dryness, which likely reduced ecosystem productivity. Seasonal total evapotranspiration (ET) ranged from 130 mm (2004) to 181 mm (2006) and varied in accordance with the precipitation received and with the timing of snow melt. Maximum daily ET rates ranged from 2.3 to 2.7 mm day −1 , occurring in mid July. Ecosystem water use efficiency (WUE eco ) varied slightly between years, ranging from 2.2 in the driest year to 2.5 in the year with intermediate rainfall amounts. In the wettest year, increased soil evaporation may have contributed to a lower WUE eco (2.3). We speculate that most, if not all, of the modest growing season CO 2 sink measured at this site could be lost due to fall and winter respiration leading to the tundra being a net CO 2 source or CO 2 neutral on an annual basis. However, this hypothesis is untested as yet.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".